The cellular, genetic, and biochemical bases of differences among inbred mice in the behaviors open field activity, defecation in the open field, cricket attacking, rope climbing, and alcohol preference are being investigated. A/J mice differ from C57-BL/6J mice in these behaviors. We are using A -- C57 chimeras to identify the cell populations which control the behaviors. Recombinant inbred (RI) strains derived from A and C57 parents are being used to enumerate and to map the genes controlling the behaviors. Biochemical and anatomical differences among the strains are being sought, and the relationship between such differences and behaviors will be studied in the RI strains. Our long term goal is to learn what genes control these behaviors, where the genes map, what their products are, in what cells they act, and what biochemical pathways they affect in affecting behavior.